Phytochemical diversity impacts herbivory in a tropical rainforest tree community

Abstract

Metabolomics provides an unprecedented window into diverse plant secondary metabolites that represent a potentially critical niche dimension in tropical forests underlying species coexistence. Here, we used untargeted metabolomics to evaluate chemical composition of 358 tree species and its relationship with phylogeny and variation in light environment, soil nutrients, and insect herbivore leaf damage in a tropical rainforest plot. We report no phylogenetic signal in most compound classes, indicating rapid diversification in tree metabolomes. We found that locally co‐occurring species were more chemically dissimilar than random and that local chemical dispersion and metabolite diversity were associated with lower herbivory, especially that of specialist insect herbivores. Our results highlight the role of secondary metabolites in mediating plant–herbivore interactions and their potential to facilitate niche differentiation in a manner that contributes to species coexistence. Furthermore, our findings suggest that specialist herbivore pressure is an important mechanism promoting phytochemical diversity in tropical forests.

The evolution of chemodiversity in plants—From verbal to quantitative models

“…However, patterns of chemical traits between species have been compared to null models for trait evolution on a phylogeny. For example, Volf et al (2018) and Wang et al (2023) used Brownian motion and white noise models. So far, however, these models cannot address intraspecific chemodiversity.…”

“…(2018) and Wang et al. (2023) used Brownian motion and white noise models. So far, however, these models cannot address intraspecific chemodiversity.…”

Functional genomics and co‐occurrence in a diverse tropical tree genus: The roles of drought‐ and defence‐related genes

“…Measurements of plant-water relations and plant defence are possible, but traditional approaches can be challenging to broadly employ. This had led to important innovations that permit measures of traits like leaf osmotic potentials (Bartlett et al, 2012) or the metabolomic profiles of species on a community scale (Sedio et al, 2012;Wang et al, 2022Wang et al, , 2023). An alternative, but under-utilized approach, has been functional genomics or transcriptomics (Swenson et al, , 2023Swenson & Jones, 2017).…”

Phytochemical drivers of insect herbivory: a functional toolbox to support agroecological diversification

“…This perspective is promising to test the ‘associational resistance’ hypothesis coined by Tahvanainen & Root [ 34 ], who assumed that phytochemical dissimilarity between neighbouring plants reduces the colonization of crop covers by pests. High-throughput metabolomics has opened a new era for plant ecologists interested in the mechanisms underlying associational resistance in plant communities like grasslands [ 35 , 36 ] or tropical forests [ 37 , 38 ]. Transposing this question into agroecosystems could help develop innovative strategies for the diversification of agroecological crop cover.…”